This invention relates to a system for performing automatic irrigation of soil containing plants or other vegetation based upon the constant monitoring of the moisture content of the soil. The present invention ensures water conservation, especially when used in large scale applications.
For the individual plant owner, the present invention ensures a constant periodic supply of water to multiple potted plants for an extended period of time without the inconvenience and guesswork associated with manual watering of the plants. The irrigation control system of the present invention also provides an aesthetically pleasing display of the plants being watered. Unlike the irrigation systems which employ capillary action (wicks) to effect watering, such as disclosed in U.S. Pat. No. 4,171,593, the present invention may also allow periodic drying out of the roots prior to rehydration if desirable, which thereby ensures the health of the plants. Because the present invention provides watering of the plants from above the soil, harmful salts do not accumulate in the soil as occurs with irrigation systems that employ capillary action, which pulls water up from below.
Moisture sensitive irrigation systems are generally known. In particular, my own U.S. Pat. No. 5,020,261 discloses a self-watering planter which activates a watering mechanism when the weight of a liner filled with soil decreases through evaporation of water. However, this self-watering planter is completely self-contained, in that the water supply, liner and moisture detecting mechanisms are all integrally combined within the planter housing. Thus, it is not possible to utilize the self-watering feature with conventional planters or pots, and separate units are required for each plant.
Additionally, large area irrigation control systems are disclosed in U.S. Pat. Nos. 2,577,337 and 2,781,228. These control systems are characterized by complex counterweight balancing control and valve mechanisms, and complicated electrical circuitry. Consequently, there exists a need in the art to provide a simpler, more cost-effective irrigation control system which overcomes the disadvantages of the prior art.